By making food smaller, easier to consume, and single-serving, manufacturers are actually leading people to eat more.

Portion sizes are out of control these days, and that's not just true for those super-size fries at fast food joints. Packaged food makers have been cleverly developing ways to ensure we eat even more of their smallest products, too. They figured out that even bite-sized candy bars provided a visual cue for people to stop eating — the wrappers would pile up, causing people to stop and assess what they'd eaten so far — so they introduced an even easier way to get what they call "hand-to-mouth" foods in, well, your mouth.

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By putting smaller versions of our favorite candies such as Twizzlers and Rolos in resealable bags, Hershey Co. found that consumers were much more likely to keep nibbling throughout the day because of the convenient packaging. Unlike their individually wrapped, "bite-size" candy bar brethren, resealable packages encourage more frequent snacking since they're convenient, mess-free, and it's harder to gauge how much you've eaten when you're just putting your hand in the bag.

Companies also know that a huge bag of chips might send a visual message of "whoa, that's way too much for you to eat all of" to your brain, but consumers will eat everything in a much smaller bag that looks like a single serving — but definitely isn't. Don't fall into the "small" trap: For any packaged food, pour out the serving size, then put the rest of the bag away.